JP2018170235A - Nonaqueous electrolyte secondary battery and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery which can be manufactured with a good yield by suppressing a break in a current collecting part of an electrode in manufacturing and a damage to an electrode body in welding.SOLUTION: A nonaqueous electrolyte secondary battery disclosed herein comprises: an electrode body arranged by laminating a plurality of electrodes; and a nonaqueous electrolyte. Each electrode has: a current collector; and an active material layer formed on the current collector. Each electrode has a current collecting part which is an active material layer non-formed part. The current collecting parts of the electrodes are collectively pinched and held by corresponding members of electrode collector terminals composed of two or more members in a lamination direction of the electrode body. The current collecting parts of the electrodes are welded to the corresponding members pinching and holding the current collecting parts.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a non-aqueous electrolyte secondary battery and a manufacturing method thereof.

  In recent years, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries have been used for portable power sources such as personal computers and portable terminals, and vehicle drives such as electric vehicles (EV), hybrid vehicles (HV), and plug-in hybrid vehicles (PHV). It is suitably used for power sources for automobiles.

  A typical lithium ion secondary battery has a configuration in which an electrode body in which positive and negative electrodes are stacked and a nonaqueous electrolyte are accommodated in a battery case. Such an electrode body is normally electrically connected to an electrode external terminal provided in the battery case via an electrode current collecting terminal. When manufacturing a lithium ion secondary battery having such a configuration, the current collector provided in the electrode is collectively inserted into the slit of the electrode current collector terminal provided with a slit, and the portion protruding from the slit of the current collector is Laser welding of the electrode current collector terminal is performed (for example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 10-106536

  According to the study by the present inventors, it has been found that there is a problem that the current collector is damaged when it contacts the slit when the current collector of the electrode constituting the electrode body is inserted into the slit. In addition, the damage of the current collector can be suppressed by increasing the width of the slit. However, if the width of the slit is increased, the laser easily passes the slit during laser welding and easily damages the electrode body. It turns out that there is a problem of becoming. Such damage to the current collector of the electrode and damage to the electrode body at the time of welding cause defective parts and defective products, and thus reduce the yield of non-aqueous electrolyte secondary batteries.

  Accordingly, an object of the present invention is to provide a non-aqueous electrolyte secondary battery that can be manufactured with a high yield by suppressing damage to a current collecting portion of an electrode during manufacture and damage to an electrode body during welding.

The nonaqueous electrolyte secondary battery disclosed herein includes an electrode body in which a plurality of electrodes are stacked, and a nonaqueous electrolyte. Each of the electrodes includes a current collector and an active material layer formed on the current collector. Each of the electrodes has a current collector that is an active material layer non-formation part. The current collecting portions of the electrodes are collected and held in the stacking direction of the electrode bodies by the members of an electrode current collecting terminal constituted by two or more members. The current collecting part of the electrode and the member sandwiching the current collecting part are welded.
According to such a configuration, since the current collector part of the electrode body is sandwiched by a plurality of members as the electrode current collector terminal, the current collector part of the electrode body that can occur in the electrode current collector terminal provided with the slit that is a conventional technique is provided. It is possible to solve the problem that the current collector is damaged when it is inserted into the slit when it contacts the slit. In addition, since the current collector part of the electrode body is sandwiched by a plurality of members as electrode current collector terminals, the welding laser is slit due to the distortion of the electrode current collector terminals that may occur in the electrode current collector having the conventional slits. The problem of damaging the electrode body after passing through can be solved. That is, according to such a configuration, it is possible to provide a non-aqueous electrolyte secondary battery that can be manufactured with a high yield by suppressing damage to the current collector of the electrode during manufacture and damage to the electrode body during welding. it can.

In a preferred aspect of the nonaqueous electrolyte secondary battery disclosed herein, the current collectors of the electrodes of the electrode body are grouped into a plurality of groups and are sandwiched by the members of the electrode current collector terminals. The plurality of groups are arranged so as not to overlap in the stacking direction of the electrode bodies. The plurality of groups are arranged stepwise in the stacking direction of the electrode bodies.
According to such a configuration, the length in the stacking direction of the group of current collecting portions of the welded portion can be reduced, and welding becomes easy. Further, the total amount of the current collector can be reduced.

In a more preferred aspect of the nonaqueous electrolyte secondary battery disclosed herein, the electrode current collector terminal is composed of a first member and a second member. The plurality of groups are arranged stepwise and are sandwiched between the first member and the second member. In the first member and the second member, a portion sandwiching the plurality of groups has a shape that fits the plurality of stepped groups. At least one of the first member and the second member has a dimension in the stacking direction of the electrode body between a portion in contact with one group and a portion in contact with the other group in the one group. It is shorter than the dimension in the stacking direction of the abutting portion and the abutting portion of the other group.
According to such a configuration, the portion where the dimension of the member constituting the electrode current collector terminal is shortened is easily deformed in the load direction due to the load. Therefore, the current collector and the electrode current collector terminal It is possible to further improve the adhesion with the members constituting the. Therefore, it is possible to further suppress the occurrence of defects in the welded portion and further improve the yield.

In a preferred aspect of the nonaqueous electrolyte secondary battery disclosed herein, the nonaqueous electrolyte secondary battery further includes a current interrupting mechanism attached to the electrode current collector terminal.
According to such a configuration, it is possible to suppress the occurrence of malfunction of the current interruption mechanism (occurrence of improper attachment) that may occur in an electrode current collector terminal having a slit, which is a conventional technology, resulting from distortion of the electrode current collector terminal. Can do. Therefore, the yield can be further improved.

A nonaqueous electrolyte secondary battery manufacturing method disclosed herein includes a current collector and an active material layer formed on the current collector, and a current collector that is an active material layer non-formation part includes An electrode composed of two or more members by combining a step of producing a plurality of provided electrodes, a step of producing an electrode body by laminating the plurality of electrodes, and a current collector of the electrode of the electrode body It includes a step of holding the electrode body in the stacking direction of the electrode body by the member of the current collecting terminal, and a step of welding the current collecting portion of the electrode and a member holding the current collecting portion.
According to such a configuration, since the current collector of the electrode body is sandwiched by a plurality of members as electrode current collector terminals, the current collector of the electrode body, which can occur in an electrode current collector having a slit, which is a conventional technique, is provided. It is possible to solve the problem that the current collector is damaged when it is inserted into the slit when it contacts the slit. In addition, since the current collector part of the electrode body is sandwiched by a plurality of members as electrode current collector terminals, the welding laser is slit due to the distortion of the electrode current collector terminals that may occur in the electrode current collector having the conventional slits. The problem of damaging the electrode body after passing through can be solved. That is, according to such a configuration, it is possible to manufacture a nonaqueous electrolyte secondary battery with a high yield by suppressing damage to the current collector of the electrode during manufacture and damage to the electrode body during welding.

In a preferred aspect of the method for producing a nonaqueous electrolyte secondary battery disclosed herein, in the sandwiching step, the current collecting portions of the electrodes of the electrode body are grouped into a plurality of groups and the member of the electrode current collecting terminal Hold by. The plurality of groups are sandwiched so as not to overlap in the stacking direction of the electrode bodies, and the plurality of groups are sandwiched in steps in the stacking direction of the electrode bodies.
According to such a configuration, the length in the stacking direction of the group of current collecting portions of the welded portion can be reduced, and welding becomes easy. Further, the total amount of the current collector can be reduced.

In a more preferred aspect of the method for producing a nonaqueous electrolyte secondary battery disclosed herein, the electrode current collector terminal is composed of a first member and a second member. In the sandwiching step, the plurality of groups arranged in a step shape are sandwiched by the first member and the second member. In the first member and the second member, a portion sandwiching the plurality of groups has a shape that fits the plurality of stepped groups. At least one of the first member and the second member has a dimension in the stacking direction of the electrode body between a portion in contact with one group and a portion in contact with the other group in the one group. It is shorter than the dimension in the stacking direction of the abutting portion and the abutting portion of the other group.
According to such a configuration, the portion where the dimension of the member constituting the electrode current collector terminal is shortened is easily deformed in the load direction due to the load. Therefore, the current collector and the electrode current collector terminal It is possible to further improve the adhesion with the members constituting the. Therefore, it is possible to further suppress the occurrence of defects in the welded portion and further improve the yield.

In a preferred aspect of the method for manufacturing a non-aqueous electrolyte secondary battery disclosed herein, the manufacturing method further includes a step of attaching a current interruption mechanism to the electrode current collector terminal.
According to such a configuration, it is possible to suppress the occurrence of malfunction of the current interruption mechanism (occurrence of improper attachment) that may occur in an electrode current collector terminal having a slit, which is a conventional technology, resulting from distortion of the electrode current collector terminal. Can do. Therefore, the yield can be further improved.

It is sectional drawing which shows typically the structure of the lithium ion secondary battery which concerns on one Embodiment of this invention. 1 is an exploded perspective view of a part of an electrode body of a lithium ion secondary battery according to an embodiment of the present invention. (A) It is a perspective view of the side edge part by the side of the positive electrode of the electrode body of the lithium ion secondary battery which concerns on one Embodiment of this invention, (b) It is a side view by the side of the positive electrode of the said electrode body. (A) It is a perspective view of the side edge part by the side of the positive electrode of the electrode body with which the 1st modification of the lithium ion secondary battery which concerns on one Embodiment of this invention is equipped, (b) The side surface by the side of the positive electrode of the said electrode body FIG. (A) It is a perspective view of the side edge part by the side of the positive electrode of the electrode body with which the 2nd modification of the lithium ion secondary battery which concerns on one Embodiment of this invention is equipped, (b) The side surface by the side of the positive electrode of the said electrode body It is a figure, (c) It is a top view of one member which comprises a positive electrode current collection terminal. It is a perspective view which shows the electrode body produced at the electrode body production process of the manufacturing method of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a figure which shows typically the clamping process of the manufacturing method of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a perspective view which shows the electrode body produced at the electrode body production process of the manufacturing method of the 1st modification of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a perspective view which shows the positive electrode current collection terminal used at the clamping process of the manufacturing method of the 2nd modification of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a perspective view of the side edge part by the side of the positive electrode of the electrode body of lithium ion secondary battery B and C examined.

  Embodiments according to the present invention will be described below with reference to the drawings. Note that matters other than the matters specifically mentioned in this specification and necessary for the implementation of the present invention (for example, a general configuration and manufacturing process of a nonaqueous electrolyte secondary battery that does not characterize the present invention) Can be understood as a design matter of those skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. Moreover, in the following drawings, the same code | symbol is attached | subjected and demonstrated to the member and site | part which show | plays the same effect | action. In addition, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships.

FIG. 1 is a cross-sectional view schematically showing a configuration of a lithium ion secondary battery 100 which is an example of a nonaqueous electrolyte secondary battery according to the present embodiment.
In the present specification, the “secondary battery” refers to a general power storage device that can be repeatedly charged and discharged, and is a term including a power storage element such as a so-called storage battery and an electric double layer capacitor. In the present specification, the “lithium ion secondary battery” refers to a secondary battery that uses lithium ions as a charge carrier and is charged and discharged by movement of charges accompanying the lithium ions between the positive and negative electrodes.

  The lithium ion secondary battery 100 includes an electrode body 10A in which a plurality of electrodes are stacked, and a nonaqueous electrolyte 90. The electrode body 10 </ b> A and the nonaqueous electrolyte 90 are accommodated in the battery case 80. The battery case 80 includes a case body 82 having an opening and a case lid 84 that closes the opening. The case lid 84 has a safety valve (not shown) set to release the internal pressure when the internal pressure of the battery case 80 rises above a predetermined level, and a liquid injection port for injecting the nonaqueous electrolyte 90. (Not shown). As a material of the battery case 80, here, a metal material (for example, aluminum) that is lightweight and has good thermal conductivity is used, but is not limited thereto, and for example, a resin may be used.

As shown in FIG. 1, the positive electrode 20 of the electrode body 10A is connected to the positive external terminal 72 attached to the case lid 84 via the positive current collector terminal 50A attached to the positive current collector 26A. . The negative electrode 30 of the electrode body 10A is connected to a negative electrode external terminal 74 attached to the case lid 84 via a negative electrode current collector terminal 60A attached to the negative electrode current collector 36A.
In FIG. 1, a current interrupt mechanism (CID) 76 is provided in a path between the positive electrode current collecting terminal 50 </ b> A and the positive electrode external terminal 72. The current interrupting mechanism 76 includes an inversion plate that inverts and interrupts the current when the internal pressure of the battery case 80 rises above a predetermined level. The current interrupt mechanism 76 may be attached to the negative electrode current collector terminal 60A and provided in a path between the negative electrode current collector terminal 60A and the negative electrode external terminal 74.

  As the non-aqueous electrolyte 90, the same one as a conventional lithium ion secondary battery (for example, a non-aqueous electrolyte in which a supporting salt such as a lithium salt is dissolved in a non-aqueous solvent such as carbonates) may be used. it can.

FIG. 2 shows an exploded perspective view of a part of the electrode body 10 </ b> A of the lithium ion secondary battery 100. The symbol W in the drawing indicates the width direction of the lithium ion secondary battery 100, the symbol D indicates the thickness direction of the lithium ion secondary battery 100, and the symbol H indicates the height direction of the lithium ion secondary battery 100. .
The electrode body 10 </ b> A has a structure in which a positive electrode 20 and a negative electrode 30 are stacked with a separator 40 interposed therebetween. Although omitted in the figure, a plurality of positive electrodes 20 and a plurality of negative electrodes 30 are alternately stacked with separators 40 interposed therebetween. The stacking direction of the electrode body 10A is the thickness direction D here.

  The positive electrode 20 includes a positive electrode current collector 22 and a positive electrode active material layer 24 formed on the positive electrode current collector 22. For the positive electrode current collector 22, for example, a metal foil such as an aluminum foil is preferably used. In the illustrated example, the positive electrode active material layer 24 is provided on both surfaces of the positive electrode current collector 22. In the width direction W, the positive electrode active material layer 24 is formed with the same width as the entire width of the positive electrode current collector 22 except for the positive electrode current collector 26A.

The positive electrode active material layer 24 contains a positive electrode active material. As the positive electrode active material, one kind or two or more kinds of substances conventionally used as a positive electrode active material in lithium ion secondary batteries can be used without particular limitation. Examples thereof include lithium nickel cobalt manganese composite oxide (eg, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ etc.), lithium nickel composite oxide (eg, LiNiO ₂ etc.), lithium cobalt composite oxide. Examples thereof include lithium transition metal composite oxides such as (eg, LiCoO ₂ ) and lithium nickel manganese composite oxides (eg, LiNi _0.5 Mn _1.5 O ₄ ). In addition to the positive electrode active material described above, the positive electrode active material layer 24 may contain a conductive material such as acetylene black (AB), or a binder such as polyvinylidene fluoride (PVDF) or styrene butadiene rubber (SBR). .

  The positive electrode 20 has a positive electrode current collector (that is, a positive electrode current collector foil) 26 </ b> A that is a positive electrode active material layer non-formation part protruding in the width direction W from the side surface of the electrode body 10 </ b> A. In this positive electrode current collector 26A, since the positive electrode active material layer 24 is not formed, the positive electrode current collector 22 is exposed. Note that the shape of the positive electrode current collector 26A is not limited to that illustrated. The position in the height direction H of the positive electrode current collector 26A changes as described later.

  The negative electrode 30 includes a negative electrode current collector 32 and a negative electrode active material layer 34 formed on the negative electrode current collector 32. For the negative electrode current collector 32, for example, a metal foil such as a copper foil is preferably used. In the illustrated example, the negative electrode active material layer 34 is provided on both surfaces of the negative electrode current collector 32. In the width direction W, the negative electrode active material layer 34 is formed with the same width as the entire width of the negative electrode current collector 32 except for the negative electrode current collector 36A.

  The negative electrode active material layer 34 contains a negative electrode active material. As the negative electrode active material, one kind or two or more kinds of substances conventionally used as a negative electrode active material in a lithium ion secondary battery can be used without any particular limitation. Examples thereof include carbon materials such as graphite carbon and amorphous carbon, and lithium transition metal nitrides. The negative electrode active material layer 34 may contain a binder such as polyvinylidene fluoride (PVDF) and styrene butadiene rubber (SBR), and a thickener such as carboxymethyl cellulose (CMC) in addition to the negative electrode active material described above. Good.

  The negative electrode 30 has a negative electrode current collector (that is, negative electrode current collector foil) 36 </ b> A that is a negative electrode active material layer non-formation part protruding in the width direction W from the side surface of the electrode body 10 </ b> A. The negative electrode current collector 36A protrudes in the opposite direction to the positive electrode current collector 26A. In this negative electrode current collector 36A, since the negative electrode active material layer 34 is not formed, the negative electrode current collector 32 is exposed. Note that the shape of the negative electrode current collector 36A is not limited to that illustrated. The position in the height direction H of the negative electrode current collector 36A changes as described later.

  The separator 40 is an insulating member that separates the positive electrode 20 and the negative electrode 30. In this example, the separator 40 is made of a sheet material having a predetermined width having a plurality of minute holes. As the separator 40, for example, a single layer structure separator or a multilayer structure separator made of a porous polyolefin-based resin can be used. The separator 40 may have a heat resistant layer (HRL).

FIG. 3A is a perspective view of the side end of the electrode body 10A on the positive electrode 20 side. FIG. 3B shows a side view of the electrode body 10A on the positive electrode 20 side.
As shown in FIG. 3, the positive electrode current collecting terminal 50A is composed of two members, a first terminal member 52A and a second terminal member 54A. The upper surface of the positive electrode current collecting terminal 50 </ b> A is a surface that contacts the current interrupt mechanism 76.
The plurality of positive electrode current collectors 26 </ b> A are divided and grouped into three groups by changing their positions. The three groups are arranged in a staircase pattern. That is, the positions of the three groups are changed in order from one end of the electrode body 10A toward the other end along the stacking direction of the electrode body 10A. And the part which clamps the group of the positive electrode current collection part 26A of the terminal member 52A and the terminal member 54A has a shape suitable for a plurality of step-like groups, and each group includes the terminal member 52A and the terminal member. 54A is sandwiched in the stacking direction.
Further, the positive electrode current collector 26A is welded to the terminal member 52A and the terminal member 54A, and a welded portion 28A is formed. The length L2 in the height direction H of the welded portion 28A is shorter than the length L1 in the height direction in which one group of the positive electrode current collector portion 26A comes into contact with the terminal member 52A and the terminal member 54A.

Since the positive electrode current collector 26A is sandwiched between a plurality of terminal members (the first terminal member 52A and the second terminal member 54A), the current collector of the electrode body that can occur in the electrode current collector terminal having a slit, which is a conventional technique. When the part is inserted into the slit, the problem that the current collecting part is damaged due to contact with the slit can be solved. Further, since the positive electrode current collector 26A is sandwiched between a plurality of terminal members (the terminal member 52A and the terminal member 54A), the electrode current collector terminal can be welded due to the distortion of the electrode current collector terminal, which can occur in the electrode current collector having a slit according to the prior art. The problem that the laser passes through the slit and damages the electrode body can be solved.
In addition, it is possible to suppress the occurrence of malfunction of the current interruption mechanism (occurrence of improper attachment) due to the distortion of the electrode current collecting terminal.

In addition, the number of groups comprised by the divided | segmented positive electrode current collection part 26A is not restricted to the example of illustration. When the electrode body 10A is thin, the positive electrode current collector 26A may be only one group.
From the viewpoint of the reliability of the welded portion 28, the positive electrode current collector 26A (ie, the positive electrode current collector foil) 26A constituting the group in a state where the positive electrode current collectors 26A, the terminal member 52A, and the terminal member 54B are in close contact with each other. All are preferably welded.
Therefore, the number of groups of the positive electrode current collector 26A (in other words, the number of divisions of the positive electrode current collector 26A) is plural, and the plurality of groups are arranged so as not to overlap in the stacking direction of the electrode body 10A. The plurality of groups are preferably arranged in steps in the stacking direction of the electrode body 10A.
If it does in this way, the length of the lamination direction of the group of 26 A of positive electrode current collection parts of the welding part 28 can be made small, and welding will become easy. Further, the total amount of the positive electrode current collector 26A can be reduced.

  In addition, it is more preferable that the number of groups constituted by the divided positive electrode current collectors 26A is 2 or more and 6 or less. If the number of groups is too small, the number of positive electrode current collectors (that is, positive electrode current collector foils) 26A per one welded portion 28 increases, so the length of the group stacking direction (also direction D in FIG. 2) is long. growing. When the length of the group in the stacking direction is large, it is necessary to increase the length of the positive electrode current collector 26A in the protruding direction. This is because, when welding, the positive electrode current collector 26A is grouped and the group is sandwiched between the terminal member 52A and the terminal member 54B, and the positive electrode current collector 26A is inserted between the terminal member 52A and the terminal member 54B. This is so that it protrudes. When the length of the group in the stacking direction is large, the length that protrudes from between the terminal member 52A and the terminal member 54B increases toward the center of the group. As a result, the heat required for welding becomes larger, which may cause an adverse effect on the separator 40 of the electrode body 10A due to a large amount of heat during welding, and increase in cost due to an increase in the size of the apparatus required for welding. There is. On the other hand, if the number of groups becomes too large, the shape of the positive electrode current collector terminal 50A may be complicated, and the positioning accuracy when the positive electrode current collector portion 26A is held becomes higher, and the positioning work becomes complicated. There is a risk of becoming.

  The positive current collecting terminal 50A is composed of two members, that is, a terminal member 52A and a terminal member 54A, but is composed of more than two members according to the number of groups of the positive current collecting portion 26A. May be.

  In FIG. 3, the plurality of groups of the positive electrode current collector 26A are arranged so as not to overlap in the stacking direction of the electrode body 10A, and the plurality of groups are arranged stepwise in the stacking direction of the electrode body 10A. As shown, the three groups are arranged in a staircase pattern. However, the arrangement of the positive electrode current collector 26A is not limited to a step shape.

FIG. 4 shows an electrode body 10B provided in the first modification of the lithium ion secondary battery 100 according to this embodiment. 4A is a perspective view of a side end portion on the positive electrode side of the electrode body 10B, and FIG. 4B is a side view of the positive electrode side of the electrode body 10B.
As shown in FIG. 4, the positive electrode current collecting terminal 50B is composed of two members, a first terminal member 52B and a second terminal member 54B.
The plurality of positive electrode current collectors 26B are divided into three groups and collected. Unlike the example of FIG. 3, in this example, the three groups are not arranged stepwise. However, the three groups are arranged so as not to overlap in the stacking direction of the electrode body 10B, and a plurality of groups are arranged in a stepwise manner in the stacking direction of the electrode body 10B.
The portions of the terminal member 52B and the terminal member 54B that sandwich the group of the positive electrode current collector portion 26B have shapes that fit these groups, and each group is sandwiched between the terminal member 52B and the terminal member 54B. Yes.
Further, the positive electrode current collector 26B is welded to the terminal member 52B and the terminal member 54B, and a welded portion 28B is formed.

  Also in the first modified example shown in FIG. 4, the number of groups of the positive electrode current collector 26B is plural, and the plural groups are arranged so as not to overlap in the stacking direction of the electrode body 10B. Since the plurality of groups are arranged stepwise in the stacking direction of the electrode body 10B, the reliability of the welded portion 28B is high.

FIG. 5 shows an electrode body 10 </ b> C included in a second modification of the lithium ion secondary battery 100 according to this embodiment. FIG. 5A is a perspective view of a side end portion on the positive electrode side of the electrode body 10C, FIG. 5B is a side view of the positive electrode side of the electrode body 10C, and FIG. It is a top view of one member 54C which constitutes terminal 50C.
As shown in FIG. 5, the positive electrode current collecting terminal 50C is composed of two members, a first terminal member 52C and a second terminal member 54C.
The plurality of positive electrode current collectors 26C are divided into three groups and collected. The three groups are arranged in a staircase pattern.
The portions of the terminal member 52C and the terminal member 54C that sandwich the group of the positive electrode current collector 26C have shapes that fit these groups, and each group is sandwiched between the terminal member 52C and the terminal member 54C. Yes.
Further, the positive electrode current collector 26C is welded to the terminal member 52C and the terminal member 54C, and a welded portion 28C is formed.

In the second modification, the shape of the terminal member 54C of the positive electrode current collecting terminal 50C is different from the example shown in FIG. Specifically, in the second modified example, the terminal member 54C of the positive electrode current collecting terminal 50C is also formed in a stepped shape at the end opposite to the end that sandwiches the group in the stacking direction of the electrode body 10C. Yes.
Accordingly, the dimension Lc in the stacking direction of the electrode body 10C (of the portion 54Cc) between the portion 54Ca that contacts the one group of the terminal member 50C and the portion 54Cb that contacts the other group corresponds to the one group. The dimension La of the contacting part 54Ca in the stacking direction and the dimension Lb of the part 54Cb contacting the other group in the stacking direction are shorter.
According to such a configuration, when the positive electrode current collector 26C is sandwiched between the terminal member 52C and the terminal member 54C, the portion 54Ca that comes into contact with one group of the terminal member 50C, and the portion 54Cb that comes into contact with another group Since the portion 54Cc having a short dimension between the positive electrode current collector 26C, the terminal member 52C, and the terminal member 54C can be further improved because deformation in the load direction of the terminal due to the load is easily performed. Therefore, it is possible to further suppress the occurrence of defects in the welded portion and further improve the yield.
In the other terminal member 52C of the positive electrode current collecting terminal 50C, the dimension in the stacking direction of the electrode body between the portion in contact with one group and the portion in contact with the other group corresponds to the one group. You may make it shorter than the dimension of the lamination direction of the part which contact | connects, and the part contact | abutted to the said other group. Moreover, it is good also as such a structure in both the terminal member 52C and the terminal member 54C.

  In each of the above examples, only the positive electrode 20 side has been specifically described, but the negative electrode 30 side has the same configuration. However, only one of the positive electrode 20 side and the negative electrode 30 side may have the above-described configuration.

Next, a method for manufacturing the nonaqueous electrolyte secondary battery according to the present embodiment will be described. The nonaqueous electrolyte secondary battery according to the present embodiment includes a current collector and an active material layer formed on the current collector, and a current collector that is an active material layer non-formation portion is provided. A process for producing a plurality of electrodes (electrode production process), a process for producing an electrode body by laminating the plurality of electrodes (electrode body production process), and a current collector of the electrodes of the electrode body A step of sandwiching the electrode body in the stacking direction of the electrode body by the member of the electrode current collector terminal composed of the above members (a sandwiching process), and a step of welding the current collector portion of the electrode and the member sandwiching the electrode body (Welding process).
Hereinafter, with reference to the drawings, the above-described lithium ion secondary battery 100 (lithium ion secondary battery 100 illustrated in FIGS. 1 to 3) is taken as an example, and the method for manufacturing the nonaqueous electrolyte secondary battery according to this embodiment is described below. Will be described in detail.

In the electrode manufacturing step, a positive electrode 20 and a negative electrode 30 as shown in FIG. 2 are manufactured.
The positive electrode 20 can be manufactured according to a known method. For example, a paste containing the constituent components of the positive electrode active material layer 24 is applied onto the positive electrode current collector 22. At this time, application is performed so as to provide a portion where the paste is not applied along one end of the positive electrode current collector 22. That is, it coat | covers so that the positive electrode electrical power collector 22 may be exposed along one edge part. The applied paste is dried and pressed as necessary to form the positive electrode active material layer 24. The portion where the positive electrode current collector 22 is exposed is cut so that the positive electrode current collector 26A is formed.
The negative electrode 30 can be manufactured by a known method. For example, a paste containing the constituent components of the negative electrode active material layer 34 is applied on the negative electrode current collector 32. At this time, application is performed so as to provide a portion where the paste is not applied along one end of the negative electrode current collector 32. That is, the negative electrode current collector 32 is applied so as to be exposed along one end. The applied paste is dried and pressed as necessary to form the negative electrode active material layer 34. The portion where the negative electrode current collector 32 is exposed is cut so that the negative electrode current collector 36A is formed.
As shown in FIG. 3, in the electrode body 10A, when the positive electrode current collector 26A and the negative electrode current collector 36A are divided and grouped together, the positive electrode 20 and the negative electrode current collector 36A are located at different positions. Several negative electrodes 30 are prepared.

In the electrode body manufacturing step, a plurality of positive electrodes 20 and negative electrodes 30 are stacked to manufacture an electrode body 10A as shown in FIG. At this time, in order to insulate the positive electrode 20 and the negative electrode 30, the separator 40 is interposed between the positive electrode 20 and the negative electrode 30. Further, the positive electrode current collector 26A and the negative electrode current collector 36A are stacked while being aligned with each other. In the illustrated example, the positive electrode current collector 26A and the negative electrode current collector 36A are each divided into three groups, and each group has a block shape. The three block groups are arranged in a staircase pattern.
This step can be performed according to a known method.

The sandwiching step will be specifically described with reference to FIG. 7 only for the positive electrode 20 side of the electrode body 10A, but the sandwiching step can be similarly performed for the negative electrode 30 side.
In the sandwiching step, as shown in FIG. 7, a positive electrode current collecting terminal 50A composed of two or more members (here, the first terminal member 52A and the second terminal member 54A) is prepared. Then, the terminal member 52A and the terminal member 54A are sandwiched in the stacking direction by the terminal member 52A and the terminal member 54A, respectively, and the terminal member 52A and the terminal member 54A are fixed.
In the illustrated example, in this way, the positive electrode current collectors 26A of the electrode body 10A are combined into a plurality of groups and sandwiched between the terminal members 52A and the terminal members 54A of the positive electrode current collector terminal 50A. The plurality of groups are sandwiched so as not to overlap each other in the stacking direction of the electrode body 10A, and the plurality of groups are sandwiched in steps in the stacking direction of the electrode body 10A.

In the welding process, the terminal member 52A and the terminal member 54A are used to weld the portion sandwiching the positive electrode current collector 26A by laser welding or the like. As a result, as shown in FIG. 3, a welded portion 28A in which the positive electrode current collector 26A is joined to the terminal member 52A and the terminal member 54A is formed. The welding process can be similarly performed on the negative electrode 30 side.
As described above, the electrode body 10A can be manufactured.

In the method for manufacturing a nonaqueous electrolyte secondary battery according to the present embodiment, a step of using the nonaqueous electrolyte secondary battery using the electrode body is further performed. This step can be performed according to a known method.
As a specific example, a process of constructing the lithium ion secondary battery 100 using the electrode body 10A will be described.

First, a battery case 80 is prepared. The battery case 80 includes a case body 82 having an opening and a case lid 84 that closes the opening. The material of the battery case 80 is, for example, aluminum. The case lid 84 is provided with a safety valve (not shown) and a liquid injection port (not shown).
Further, the positive electrode current collecting terminal 50 </ b> A and the negative electrode current collecting terminal 60 </ b> A of the electrode body 10 </ b> A are joined to the positive electrode external terminal 72 and the negative electrode external terminal 74 provided on the outer side of the case lid 84, respectively.
At this time, a step of attaching the current interrupting mechanism 76 to the positive electrode current collecting terminal 50A is performed, and the current interrupting mechanism 76 is provided in the path between the positive electrode current collecting terminal 50A and the positive electrode external terminal 72 as shown in FIG. May be. The current interruption mechanism 76 may be attached to the negative electrode current collecting terminal 60A and provided in a path between the negative electrode current collecting terminal 60A on the negative electrode side and the negative electrode external terminal 74. The attachment of the current interrupt mechanism 76 can be performed according to a known method.
Subsequently, while the electrode body 10 </ b> A is housed in the case body 82, the opening of the case body 82 is closed with the case lid body 84, and then the case body 82 and the case lid body 84 are sealed.
And the nonaqueous electrolyte 90 is inject | poured from a liquid injection port, and a liquid injection port is sealed.
In this way, the lithium ion secondary battery 100 can be constructed.

In addition, when manufacturing the 1st modification of the nonaqueous electrolyte secondary battery which concerns on this embodiment, as shown in FIG. 8, in the said electrode body preparation process, as shown in FIG. In the figure, the group of the positive electrode current collector 26B only) may be arranged in a stepwise manner in the stacking direction of the electrode bodies. And in the said clamping process, what is necessary is just to use the electrode current collection terminal of the shape suitable for these groups.
When the second modification of the nonaqueous electrolyte secondary battery according to this embodiment is manufactured, the first terminal member 52C and the second terminal shown in FIG. What is necessary is just to use the positive electrode current collection terminal 50C comprised from the 2nd terminal member 54C. In the positive electrode current collecting terminal 50C, as shown in FIG. 5, in the stacking direction of the electrode body 10C of the part 54Cc between the part 54Ca that contacts the one group of the terminal member 50C and the part 54Cb that contacts the other group. The dimension Lc is shorter than the dimension La in the stacking direction of the part 54Ca in contact with one group and the dimension Lb in the stacking direction of the part 54Cb in contact with another group. A similar negative electrode current collecting terminal may be used on the negative electrode side.

  EXAMPLES Examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples.

The lithium ion secondary batteries A to C shown below were prepared and evaluated by the following procedure.
<Production of lithium ion secondary battery>
[Lithium ion secondary battery A]
In accordance with the above-described method, an electrode body having the configuration shown in FIG. 3 (same configuration on the negative electrode side) was prepared, and a lithium ion secondary battery A was manufactured using the electrode body. An aluminum foil with a thickness of 15 μm was used for the positive electrode current collector, and a copper foil with a thickness of 10 μm was used for the negative electrode current collector. The positive electrode current collector terminal was made of aluminum, and the thickness of the positive electrode current collector terminal was 1.5 mm. The negative electrode current collector terminal was made of copper, and the thickness of the negative electrode current collector terminal was 1.0 mm. The electrode body was provided with three groups of current collectors having a height in the length direction of 14 mm in a staircase pattern. The number of current collector foils (current collectors) constituting each group was 24. In addition, the electric current interruption mechanism (CID) by which the operating pressure was set to 0.7 Mpa or more was attached to the positive electrode side. Welding was performed by laser welding.

[Lithium ion secondary battery B]
An electrode body having the form shown in FIG. 10 (same configuration on the negative electrode side) was prepared, and a lithium ion secondary battery B was manufactured using the electrode body. The electrode body 110 shown in FIG. 10 includes a positive electrode current collector 126, which includes three slits 156, and is held by a positive electrode current collector terminal 150 made of a single member. The terminal 150 has a welded form. The negative electrode side also has the same form. In the lithium ion secondary battery B, the width (before pressurization) of the slit 156 of the positive electrode current collecting terminal 150 was set to 0.6 mm. An aluminum foil with a thickness of 15 μm was used for the positive electrode current collector, and a copper foil with a thickness of 10 μm was used for the negative electrode current collector. The positive electrode current collector terminal was made of aluminum, and the thickness of the positive electrode current collector terminal was 1.5 mm. The negative electrode current collector terminal was made of copper, and the thickness of the negative electrode current collector terminal was 1.0 mm. The current collector was provided along both ends of the electrode body. In addition, the electric current interruption mechanism (CID) by which the operating pressure was set to 0.7 Mpa or more was attached to the positive electrode side. 24 current collector foils (current collectors) were inserted into each slit, pressed from the width direction of the slit, and then laser welded.

[Lithium ion secondary battery C]
An electrode body having the form shown in FIG. 10 (same configuration on the negative electrode side) was produced, and a lithium ion secondary battery C was produced using the electrode body. In the lithium ion secondary battery C, the width (before pressurization) of the slit 156 of the positive electrode current collecting terminal 150 was set to 1.0 mm. An aluminum foil with a thickness of 15 μm was used for the positive electrode current collector, and a copper foil with a thickness of 10 μm was used for the negative electrode current collector. The positive electrode current collector terminal was made of aluminum, and the thickness of the positive electrode current collector terminal was 1.5 mm. The negative electrode current collector terminal was made of copper, and the thickness of the negative electrode current collector terminal was 1.0 mm. The current collector was provided along both ends of the electrode body. In addition, the electric current interruption mechanism (CID) by which the operating pressure was set to 0.7 Mpa or more was attached to the positive electrode side. 24 current collector foils (current collectors) were inserted into each slit, pressed from the width direction of the slit, and then laser welded.
The lithium ion secondary battery A corresponds to the nonaqueous electrolyte secondary battery according to the present embodiment, and the lithium ion secondary batteries B and C are conventional nonaqueous electrolyte secondary batteries.

<Evaluation of lithium ion secondary battery>
[Evaluation 1: Appearance observation of current collector]
The electrode body of each lithium ion secondary battery was examined for the presence or absence of damage to the current collector. Specifically, since the current collector is a current collector foil, the current collector foil was observed for cracks and breaks. The current collector foil was judged as non-defective if there was no tear or break, and the current collector foil was judged as defective if the current collector foil was cracked or broken. For each lithium ion secondary battery, 10 samples were evaluated. The evaluation results are shown in Table 1 as “(number of non-defective samples) / (number of fabricated samples)”.

[Evaluation 2: Measurement of CID working pressure]
The operating pressure of CID was examined for each lithium ion secondary battery. Samples having a CID operating pressure in the range of 0.7 MPa or more and 0.8 MPa or less were regarded as good products, and samples outside the range were regarded as defective products. For each lithium ion secondary battery, 10 samples were evaluated. The evaluation results are shown in Table 1 as “(number of non-defective samples) / (number of fabricated samples)”.

[Evaluation 3: Appearance Observation of Welded Electrode]
The welded portion of the electrode body of each lithium ion secondary battery was disassembled, and the presence or absence of burnout of the separator was examined. A separator that did not burn out was judged as a good product, and a separator that burned out was judged as a defective product. For each lithium ion secondary battery, 10 samples were evaluated. The evaluation results are shown in Table 1 as “(number of non-defective samples) / (number of fabricated samples)”.

As can be seen from Table 1, in the lithium ion secondary battery A corresponding to the nonaqueous electrolyte secondary battery according to this embodiment, no defective product was found in any of the evaluations 1 to 3.
On the other hand, regarding the evaluation 1, in the lithium ion secondary battery B which is the prior art, there was a sample in which a fracture was observed at a position in contact with the side surface of the slit of the current collector. This is because the slit width is narrow, and when the current collector is inserted into the slit of the current collector terminal, the current collector comes into contact with the side surface of the slit and breaks.
Regarding evaluation 2, in the lithium ion secondary batteries B and C which are the prior art, there was a sample in which the operating pressure of CID was lowered. This is because, in the conventional lithium ion secondary batteries B and C, when attaching a positive electrode current collector terminal provided with a slit, an operation to close the slit by pressing from the width direction of the slit to bring it into close contact with the current collector This is because distortion occurred on the CID mounting surface, which is the upper surface of the positive electrode current collector terminal. The lithium ion secondary battery C having a larger slit width had more defective products.
Regarding evaluation 3, in the conventional lithium ion secondary batteries B and C, there were samples in which the separator burned out. This is because, in the conventional lithium ion secondary batteries B and C, the positive current collector terminal is twisted and distorted by the operation of closing the slit, and the leg of the positive current collector terminal (the portion sandwiching the current collector) This is because a laser beam for welding has passed through the slit in the step portion. Note that the lithium ion secondary battery C having a large slit width has a larger number of defective products because the leg is more deformed and a gap through which the laser passes is easily formed.
From the above, the lithium ion secondary battery, which is the nonaqueous electrolyte secondary battery according to the present embodiment, has a yield by suppressing damage to the current collector portion of the electrode during manufacture and damage to the electrode body during welding. It can be seen that (material yield and product yield) can be manufactured well.
Moreover, when using the single current collection terminal provided with a slit like the prior art, it is necessary to collect foil before inserting a current collection part in the slit of a current collection terminal. However, the foil collection operation can be omitted when manufacturing a lithium ion secondary battery that is a nonaqueous electrolyte secondary battery according to the present embodiment.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

10A, 10B, 10C Electrode body 20 Cathode 22 Cathode current collector 24 Cathode active material layer 26A, 26B, 26C Cathode current collector 28A, 28B, 28C Weld 30 Cathode 32 Cathode collector 34 Cathode active material layer 36A Cathode collector Electric part 40 Separator 50A, 50B, 50C Positive current collecting terminal 52A, 52B, 52C First member 54A, 54B, 54C Second member 60A Negative current collecting terminal 72 Positive external terminal 74 Negative external terminal 76 Current interruption mechanism 80 Battery Case 82 Case body 84 Case lid 90 Non-aqueous electrolyte 100 Lithium ion secondary battery

Claims (8)

A non-aqueous electrolyte secondary battery comprising an electrode body in which a plurality of electrodes are laminated, and a non-aqueous electrolyte,
Each of the electrodes has a current collector and an active material layer formed on the current collector,
Each of the electrodes has a current collecting part that is an active material layer non-forming part,
The electrode current collectors are grouped together and held in the stacking direction of the electrode body by the member of the electrode current collector terminal composed of two or more members,
The current collecting part of the electrode and the member sandwiching the current collecting part are welded,
A non-aqueous electrolyte secondary battery. The electrode current collectors of the electrode body are grouped into a plurality of groups and sandwiched by the members of the electrode current collector terminals,
The plurality of groups are arranged so as not to overlap in the stacking direction of the electrode bodies,
The plurality of groups are arranged stepwise in the stacking direction of the electrode bodies,
The nonaqueous electrolyte secondary battery according to claim 1. The electrode current collector terminal is composed of a first member and a second member,
The plurality of groups are arranged stepwise and are sandwiched between the first member and the second member,
The first member and the second member have a shape in which a portion sandwiching the plurality of groups is adapted to the plurality of stepped groups,
At least one of the first member and the second member has a dimension in the stacking direction of the electrode body between a portion in contact with one group and a portion in contact with the other group in the one group. It is shorter than the dimension in the stacking direction of the abutting portion and the abutting portion of the other group,
The nonaqueous electrolyte secondary battery according to claim 2. A current interruption mechanism attached to the electrode current collector terminal;
The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3. A step of producing a plurality of electrodes including a current collector and an active material layer formed on the current collector and provided with a current collector that is an active material layer non-formation part;
Laminating the plurality of electrodes to produce an electrode body;
Collecting the electrode current collectors of the electrode body, and sandwiching the electrode body in the stacking direction of the electrode body by the member of the electrode current collector terminal composed of two or more members; and
Welding the current collector portion of the electrode and a member sandwiching the current collector portion;
A method for producing a non-aqueous electrolyte secondary battery, comprising: In the sandwiching step,
The electrode collector of the electrode body is grouped into a plurality of groups and sandwiched by the members of the electrode collector terminal,
The plurality of groups are sandwiched so as not to overlap in the stacking direction of the electrode bodies, and the plurality of groups are sandwiched in steps in the stacking direction of the electrode bodies,
The manufacturing method of the nonaqueous electrolyte secondary battery of Claim 5. The electrode current collector terminal is composed of a first member and a second member,
In the sandwiching step, the plurality of groups arranged in a staircase shape are sandwiched by the first member and the second member,
The first member and the second member have a shape in which a portion sandwiching the plurality of groups is adapted to the plurality of stepped groups,
At least one of the first member and the second member has a dimension in the stacking direction of the electrode body between a portion in contact with one group and a portion in contact with the other group in the one group. It is shorter than the dimension in the stacking direction of the abutting portion and the abutting portion of the other group,
The manufacturing method of the nonaqueous electrolyte secondary battery of Claim 6. A step of attaching a current interrupting mechanism to the electrode current collecting terminal;
The manufacturing method of the nonaqueous electrolyte secondary battery as described in any one of Claims 5-7.

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